Liquid crystallization of glassy guar gum with water

Liquid crystal formation of guar gum (GG) in the presence of water was investigated by differential scanning calorimetry. GG is a neutral galactomannan, consists of 1,4-β-d-mannose backbone and 1,6-α-d-galactose side chains, and the galactose/mannose ratio is 1:2. It was found that GG–water has a specific water content range where the liquid crystallization takes place. When GG–non-freezing water system is solidified rapidly, it was frozen into the glassy state. By heating, glass transition, cold crystallization and liquid crystallization are observed. Liquid crystallization took place at cold crystallization. By slow cooling, a part of GG molecules associated with water is liquid crystallized on cooling and the rest amount is frozen in the glassy state. Glassy region forms liquid crystal which is observed as the cold crystallization. The summation of enthalpy of liquid crystallization obtained on cooling and that of cold crystallization on heating accords well with that of transition from liquid crystal to isotropic liquid.